This is a proposal for a renewal of a longitudinal study to extend a current 5-year study relating older age to tile progression of HIV-I infection. Tile original study compared older (greater than or equal to 50) to younger (18-39) H1V+ individuals and to older and younger HIV- individuals. HIV+ individuals were in the early and late symptomatic stages of infection. Associations with older age dependent upon HIV serostatus were observed on neuropsychological performance, the symptoms of minor cognitive-motor disorder, immune measures (CD4/CD8 ratio; CD4 cell count; CD8 cell count), and plasma viral load. The renewal will focus upon recruitment of an additional 95 participants according to a matching strategy on educational level, ethnicity, and socioeconomic status. These participants will be join in the longitudinal follow-up of the original cohort and be examined for changes in neuropsychological performance using an expanded N P battery adding a domain for working memory as well as increased assessment of the motor domain. The diagnosis and symptoms of minor cognitive-motor disorder wilt likewise be studied for age-associated effects. Questions will also be directed to newly proposed outcome measures. The original study aim on differences in overall functional status will now be more focused, examining cognition-specific functional status [a defining criterion of cognitive-motor disorder]. The findings on age-associated immunologic changes (in the CD4/CD8 ratio, CD4 cell count, and CD8 cell count) will be pursued. The naive subsets of CD4 cells will be enumerated, and cytokines produced by the Thl and Th2 subsets of CD4 cells will be quantified. Regarding age-associated increases in CD8 cell count we observed in older HIV+ individuals, the cytotoxic T lymphocyte subset of CD8 cells will be enumerated. As the observed age-associated immune changes were not mediated by plasma viral load, HIV-1 protein expression will be examined together with the associated production of pro-inflammatory cytokines known to be linked to cognitive-motor impairment and disorder. Control variables have been focused upon using a data reduction strategy. The findings may have great clinical relevance for the management of older HIV-infected individuals.